In a substrate processing apparatus a workpiece (e.g., semiconductor wafer, glass substrate, or the like) is processed in a state where the workpiece is mounted on a mounting table. It is important to control the temperature of the workpiece when such a workpiece is processed. Hence, a mounting table having a temperature regulating function has been widely used.
For example, an electrostatic chuck having a temperature control function is disclosed in Japanese Patent Publication No. 06-170670. An attraction electrode and a heater are embedded in this electrostatic chuck. When a voltage is applied from an external power source, the attraction electrode generates an electrostatic force to attract and hold a workpiece on a mounting surface of the electrostatic chuck. Further, the heater generates heat by a power supplied from a heater power source to heat the electrostatic chuck. A through-hole is forming in the electrostatic chuck to extend in a plate thickness direction, and a temperature sensor is inserted into the through-hole such that a front end portion thereof comes into contact with a rear surface side of the workpiece and measures the temperature of the workpiece. A temperature control and operation unit is connected to the temperature sensor. The temperature control and operation unit controls the heater power source depending on the temperature of the workpiece obtained from the temperature sensor, so that the temperature of the workpiece is controlled to a target temperature.